The ability to hear a single important piece of information when multiple communications are in process is critical to many. For example, if one is listening to the radio or watching television and the phone rings, many would prefer to hear their phone ring so that they do not miss an important phone call. In another instance, someone may be watching a stock market report on television, trying to decide if they should buy or sell some stock when someone else in the home starts to blend a drink, vacuum a carpet or start some other household appliance that creates a significant amount of ambient noise. When this occurs, the listener/watcher often misses the desired content because the ambient or background noise obscures the desired content. Oddly enough, the ambient noise level in a home often becomes very high just as the information that the watcher has been waiting for is presented.
Another common phenomenon is when a sports fan is watching sports highlights or an important game and the furnace or air conditioning starts up, or someone comes into the room and blurts out a question, raising the ambient noise level such that the sports fan misses an important piece of information. Generally, as the noise level in a listening area increases the comprehensibility of the audio emitted from any given device decreases. To properly accommodate a listener, a constant manual adjustment of the audio level of devices is required by the user to make sure that audio devices are not too loud such as to annoy or too soft such that user misses or cannot hear desired information. Often a listener will not have a remote control for the audio device in hand to instantaneously adjust the volume based on any increase in the ambient noise level of audio. Even with a remote in a listener's hand, a user will often not be quick enough to increase the volume before the important information is missed because such phenomenon can happen very quickly.
Automatic volume control mechanisms have been utilized in telephone devices and in other audio devices such as car radios. More specifically, some convertible top cars have audio systems that increase the volume of the radio as the speed of the car increases. Such systems compensate for road and wind noise; however, these systems typically do not sense the ambient noise, but just relate the speed of the vehicle to the audio level provided.
This method of automatic volume control has many drawbacks. First, the ambient noise level is assumed based on testing and such a system does not utilize the actual ambient level to control the volume. If such a system utilized the ambient level, every time the driver talked to his passenger the radio volume would rise to the point where the driver could not carry on a conversation with the passenger. Also if a cell phone would ring the radio would increase its volume and the driver may not be able to carry on a conversation. Thus, an auto volume adjust system without some additional form of control would be impractical.